376 GENERAL SCIENCE 



as mummies, under the influence of the warm spring 

 rains, develops masses of new spores, which when carried 

 by the breeze to blossoms and green fruit start the rot 

 anew. The mummies which fall to the ground and become 

 only about half-covered produce spores which cause 

 blight of the blossoms. 



Remedy. Gather all mummies from the trees and 

 ground and either burn them or bury them more than six 

 inches deep. Spray dormant trees with lime-sulphur 

 solution, 1-8, to kill spores adhering to the limbs. Self- 

 boiled lime-sulphur spray will help to protect peaches in 

 the summer. Remove all fruit noticeably affected to 

 prevent the development of new spores. 



260. Pear Blight. Pear blight is a disease caused by 

 bacteria. It is also called fire blight. It sometimes 

 attacks rapidly growing apple and plum trees. It is 

 easily recognized by the sudden death of blossoms and 

 ends of growing twigs. The attacked leaves turn black 

 and cling to the twigs after the other leaves have fallen. 

 Sometimes the disease runs down the limbs and kills the 

 whole tree. Dead spots or cankers are formed on the 

 limbs and bodies of trees at the base of blighted spurs and 

 watersprouts. At times the fruit is affected and dries on 

 the tree. 



The bacterium lives over the winter in the cankers. 

 In the spring, sticky, milky drops, containing many 

 bacteria, run out from these hold-over cankers. Insects 

 of various kinds carry the bacteria from the cankers 

 to the flowers and tips of growing twigs. The feet 

 of the insects make very slight wounds into which the 

 bacteria can pass, and then the bacteria multiply rapidly, 

 causing the blight to become visible in from ten to four- 

 teen days. 



